This invention relates to wire reinforced hose articles, more particularly high pressure thermoplastic hydraulic hose and the like, and methods for their production.
Thermoplastic wire reinforced hose is widely used for hydraulic and other high pressure applications. This hose is generally constructed of a pre-cured or set thermoplastic tube which has substantial dimensional stability and a hard outer surface, onto which is telescoped one or more wire braid layers, and an outer protective cover. It is known that the kink resistance of wire or textile reinforced hydraulic thermoplastic hose can be improved by employing an adhesive between the tube and braid and/or between multiple braid layers, however, this practice has not been known to significantly improve impulse life of the hose. Even with the use of polymeric adhesives, impulse life of wire reinforced hose is oftentimes substantially less than required for many applications, apparently because individual wire strands of a beam of the braid during impulsing tend to abrade and/or fret as the wires rub and pantograph together. This causes premature wire fatigue.
It is a primary object of this invention to provide a method of producing a wire reinforced polymeric hose with improved life principally by reducing wire fatigue and which hose construction in operation is characterized by longer impulse life. It is another object to provide a method of producing a wire reinforced thermoplastic high pressure hose, e.g., hydraulic hose, of significantly improved impulse life while also exhibiting excellent resistance to kink.